From 9df8a4d197e66accb389edb5a5c54117933f157e Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Sun, 28 Jun 2026 00:09:06 +0200
Subject: feat(engine): add windowing DPI utilities

---
 engine/src/windowing/dpi.rs | 182 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 182 insertions(+)
 create mode 100644 engine/src/windowing/dpi.rs

(limited to 'engine/src/windowing/dpi.rs')

diff --git a/engine/src/windowing/dpi.rs b/engine/src/windowing/dpi.rs
new file mode 100644
index 0000000..2bac619
--- /dev/null
+++ b/engine/src/windowing/dpi.rs
@@ -0,0 +1,182 @@
+macro_rules! gen_struct_from_to_impls {
+    ($struct: ident, fields=($($field: ident),*)) => {
+        impl<Pixel> From<winit::dpi::$struct<Pixel>> for $struct<Pixel>
+        {
+            fn from(source: winit::dpi::$struct<Pixel>) -> Self
+            {
+                Self {
+                    $($field: source.$field),*
+                }
+            }
+        }
+
+        impl<Pixel> From<$struct<Pixel>> for winit::dpi::$struct<Pixel>
+        {
+            fn from(source: $struct<Pixel>) -> Self
+            {
+                Self {
+                    $($field: source.$field),*
+                }
+            }
+        }
+    };
+}
+
+macro_rules! gen_enum_from_to_impls {
+    ($enum: ident, variants=($($variant: ident),*)) => {
+        impl From<winit::dpi::$enum> for $enum
+        {
+            fn from(source: winit::dpi::$enum) -> Self
+            {
+                match source {
+                    $(winit::dpi::$enum::$variant(pos) => Self::$variant(pos.into())),*
+                }
+            }
+        }
+
+        impl From<$enum> for winit::dpi::$enum
+        {
+            fn from(source: $enum) -> Self
+            {
+                match source {
+                    $($enum::$variant(pos) => Self::$variant(pos.into())),*
+                }
+            }
+        }
+    };
+}
+
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct PhysicalPosition<Pixel>
+{
+    pub x: Pixel,
+    pub y: Pixel
+}
+
+impl<Pixel> PhysicalPosition<Pixel>
+{
+    pub fn to_logical<LogicalPixel>(&self, scale_factor: f64) -> LogicalPosition<LogicalPixel>
+    where
+        Pixel: Into<f64> + Clone,
+        LogicalPixel: From<f64>
+    {
+        let x = self.x.clone().into();
+        let y = self.y.clone().into();
+
+        LogicalPosition {
+            x: (x / scale_factor).into(),
+            y: (y / scale_factor).into()
+        }
+    }
+
+    pub fn try_convert_from<SourcePixel>(source: PhysicalPosition<SourcePixel>) -> Result<Self, Pixel::Error>
+    where
+        Pixel: TryFrom<SourcePixel>
+    {
+        Ok(Self {
+            x: source.x.try_into()?,
+            y: source.y.try_into()?
+        })
+    }
+}
+
+gen_struct_from_to_impls!(PhysicalPosition, fields=(x, y));
+
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct LogicalPosition<Pixel>
+{
+    pub x: Pixel,
+    pub y: Pixel
+}
+
+impl<Pixel> LogicalPosition<Pixel>
+{
+    pub fn try_convert_from<SourcePixel>(source: LogicalPosition<SourcePixel>) -> Result<Self, Pixel::Error>
+    where
+        Pixel: TryFrom<SourcePixel>
+    {
+        Ok(Self {
+            x: source.x.try_into()?,
+            y: source.y.try_into()?
+        })
+    }
+}
+
+gen_struct_from_to_impls!(LogicalPosition, fields=(x, y));
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Position
+{
+    Physical(PhysicalPosition<i32>),
+    Logical(LogicalPosition<f64>)
+}
+
+gen_enum_from_to_impls!(Position, variants=(Physical, Logical));
+
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct PhysicalSize<Pixel>
+{
+    pub width: Pixel,
+    pub height: Pixel
+}
+
+impl<Pixel> PhysicalSize<Pixel>
+{
+    pub fn to_logical<LogicalPixel>(&self, scale_factor: f64) -> LogicalSize<LogicalPixel>
+    where
+        Pixel: Into<f64> + Clone,
+        LogicalPixel: From<f64>
+    {
+        let width = self.width.clone().into();
+        let height = self.height.clone().into();
+
+        LogicalSize {
+            width: (width / scale_factor).into(),
+            height: (height / scale_factor).into()
+        }
+    }
+}
+
+impl<Pixel> PhysicalSize<Pixel>
+{
+    pub fn try_convert_from<SourcePixel>(source: PhysicalSize<SourcePixel>) -> Result<Self, Pixel::Error>
+    where
+        Pixel: TryFrom<SourcePixel>
+    {
+        Ok(Self {
+            width: source.width.try_into()?,
+            height: source.height.try_into()?
+        })
+    }
+}
+
+gen_struct_from_to_impls!(PhysicalSize, fields=(width, height));
+
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct LogicalSize<Pixel>
+{
+    pub width: Pixel,
+    pub height: Pixel
+}
+
+impl<Pixel> LogicalSize<Pixel>
+{
+    pub fn try_convert_from<SourcePixel>(source: LogicalSize<SourcePixel>) -> Result<Self, Pixel::Error>
+    where
+        Pixel: TryFrom<SourcePixel>
+    {
+        Ok(Self {
+            width: source.width.try_into()?,
+            height: source.height.try_into()?
+        })
+    }
+}
+
+gen_struct_from_to_impls!(LogicalSize, fields=(width, height));
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Size
+{
+    Physical(PhysicalSize<u32>),
+    Logical(LogicalSize<f64>)
+}
-- 
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